The key for male (and female) health: estrogen, testosterone and their siblings
The U.S. Secretary of Defense Pete Hegseth has announced that military personnel 30 or older will undergo regular testing for testosterone deficiency. This will be included in their mandatory annual checkup to optimize the person’s natural capabilities, protecting longevity and ensuring the biological foundation required to sustain the fight. The program will ensure that the troops have the right testosterone levels to “operate at their absolute best”.
Are testosterone levels what determine an individual’s natural capabilities and give them the biological foundations to sustain a fight? If so, is it still as true in 2026 with the new technologies as it was at the beginning of the 1900s?
First, when listening to Hegseth’s speech we assume he is talking about testing males. But as of today, females make up about 17-18% of the military. When asked directly about females, the answer was unclear. Interestingly, though, most people assumed that females would be tested only for estrogen and recommended estrogen replacement therapy only.
Well, biologically speaking, everyone has the same set of hormones; females also produce testosterone and males also produce estrogen. The difference is in the balance, like how a chef would add a pinch of sugar to their tomato sauce to cut the acidity. The sugar is an insignificant amount, as compared with other ingredients such as tomatoes and olive oil, but it can make such a significant difference that you can tell when it is not there or when a cook adds it.
Testosterone has been associated with masculinity and strength. Indeed, if you Google it, it is described as “the male sex hormone”. Bodybuilders (both men and women) are known to take an extra dose of testosterone to help them to grow more muscles. Men with lower than recommended levels of testosterone are encouraged to consider hormone replacement therapy.
However, male bodies think it is worth converting some testosterone into estrogen (the molecule mostly known as estradiol). This reaction happens in bones, liver and fat tissue using an enzyme called aromatase. Estradiol in men supports libido, bone health, the cardiovascular system, memory and metabolic balance.
Estrogen levels in males are still significantly lower than in females. However, estradiol is the “pinch of sugar” that can make the best tomato source — or, borrowing the words from the U.S. Secretary of Defense, “perform at your best.” So to optimize the person’s natural capabilities, evaluating estrogen is also mandatory.
Conversely, testosterone is produced by both sexual organs (testis and ovaries) and adrenal glands. It is not only responsible for sex organ maturation, but it is essential for bone health, cardiovascular health and brain functions. This is for males and females. Indeed, testosterone replacement therapy is also recommended for females in specific cases.
Hormones are responsible for communication between cells, and between us and the environment. Therefore, the balance does not only vary between sexes, but it changes depending on the time of day, lifestyle, age and events happening in people’s lives. This fast adaptation is great for survival, but it can backfire when external doses are administered. For instance, if one of them seems low and we take an external dose, our body readjusts not only for those specific hormones, but the whole balance. That is why they are hard to study.
Overall, when it is about hormones, it is clearly not a one-size-fits-all model — or even one-size-fits-most. The optimal strategy is to test everyone for testosterone and estrogen regardless of their sex or gender. Based on the results, the doctors can prescribe the best solution. Today we have more resources, such as hormone replacement therapy and lifestyle adjustment. Hegseth assures us that a team of highly qualified doctors will know what to suggest if anything is of concern.
The data we have collected so far are not sufficient to identify the “right levels” of hormones and eventually the best therapy. This initiative, while taking care of the health of the troops, can also provide the data we need to crack the hormone code. I hope that this precious data will be shared with the scientific community (de-identified, of course). This constitutes a significant contribution to identifying the “right levels” for a healthy life and to “operate at their absolute best.”
